cat5241 Catalyst Semiconductor, cat5241 Datasheet - Page 7

• Manufacturer Part Number: cat5241
• Description: Quad Digitally Programmable Potentiometers Dpp? With 64 Taps And I?c Interface
• Manufacturer: Catalyst Semiconductor

WRITE OPERATION
In the
START condition and the slave address information to
the Slave device. After the Slave generates an
acknowledge, the Master sends the instruction byte
that defines the requested operation of CAT5241. The
instruction byte consist of a four-bit opcode followed
by two register selection bits and two pot selection
bits. After receiving another acknowledge from the
Slave, the Master device transmits the data to be
written into the selected register. The CAT5241
acknowledges once more and the Master generates
the STOP condition, at which time if a non-volatile
data register is being selected, the device begins an
internal programming cycle to non-volatile memory.
While this internal cycle is in progress, the device will
not respond to any request from the Master device.
Figure 5. Slave Address Bits
*
** A0, A1, A2 and A3 must compare to its corresponding hard wired input pins.
Figure 6. Write Timing
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
A0, A1, A2 and A3 correspond to pin A0, A1, A2 and A3 of the device.
Write mode, the Master device sends the
BUS ACTIVITY:
SDA LINE
MASTER
CAT5241
S
T
A
R
T
S
Fixed
SLAVE/DPP
ADDRESS
0
Variable
1
A
C
K
0
op code
INSTRUCTION
7
Acknowledge Polling
The disabling of the inputs can be used to take
advantage of the typical write cycle time. Once the
stop condition is issued to indicate the end of the
host's write operation, the CAT5241 initiates the
internal write cycle. ACK polling can be initiated
immediately. This involves issuing the start condition
followed by the slave address. If the CAT5241 is still
busy with the write operation, no ACK will be returned.
If the CAT5241 has completed the write operation, an
ACK will be returned and the host can then proceed
with the next instruction operation.
BYTE
1
Pot/WCR
Address
A3
Data Register
Address
A
C
K
A2
DR WCR DATA
A1
A0
A
C
K
P
O
S
T
P
Doc. No. MD-2011 Rev. O
CAT5241